Should we be Worried?

As we approach the coming New Year, it seems that we've got a lot to worry about. The Prime Minister keeps beating the drum about the impending danger of a nuclear Iran; rockets are still falling on Sederot (which is pretty close to where I live), and gasoline reached an all-time high this week (what goes up doesn't seem to want to go down, either!) All of these worries don't even begin to touch on the personal concerns each of has for our families; for their health and well-being; for our children's continued growth and development. As I said, there's a lot to worry about.
But should we worry? Is worry something good and positive, or is it an emotion we should specifically try to control and minimize to whatever degree possible? The answer, of course, is that it depends on the subject of our worry.
In the classic Mussar work אורחות צדיקים, the anonymous author describes worry as a negative, destructive trait.

הדאגה. זאת המידה היא רעה ברוב ענייניה, והיא ניכרת על כל הפנים, כדכתיב (בראשית מ ו): "וירא אתם והינם זועפים"; וכתיב (נחמיה ב ב): "מדוע פניך רעים, ואתה אינך חולה". ואמר אחד מן החכמים: איני מוצא כלל באנשי נפשות העליונות סימן דאגה. הדואג על עולם זה להשיג מאומה – הוא מגונה מאוד, והיא לא נמצאת כלל באנשים הבוטחים בשם ומאמינים בו. הדאגה והיגון הם מכלים הלב, והם חולי הגוף. והדאגה הרעה שבכל הדאגות היא שירדוף אחר העבירות, ובעת שלא ימצא כל חפץ לבו – אז הוא דואג ומצטער. הדואג על עולם זה הוא רחוק מאוד מן התורה והמצוות והתפילה. לכן יחוש מאוד לתקן המידה הזאת, להסיר אותה ממנו. ואין צריך להאריך ברעתה, כי כל הטובות הבאות מן השמחה – הן היפוך הדאגה.

Worry. This attribute is almost always negative, and is recognizable on every face, as it is written, "And [Yosef] saw them and they were sad." (Bereishit 40:6) and it is also written, "Why is your face sad, and you are not sick." And one of the scholars has said, I have not seen worry in the spirits of the higher-level souls. On who worries about achieving anything in this world – this is very obscene – and is not found in those people who trust in God and have faith in Him. Worry and anguish destroy the heart and they are sicknesses of the body…Thus, a person should make great effort to fix this attribute and remove it from himself. And there's no reason to write at length about the negative nature [of worry] because all of the goodness that comes from happiness – is the direct opposite of worry.

In essence, "Don't worry, be happy."
But there is a type of worry that is positive and productive. We find in the Gemara in Brachot (4a) that although David Hamelech considered himself generally righteous, telling God שמרה נפשי כי חסיד אני – "Save my soul, for I am righteous" (Tehillim 86:1), nonetheless at the end of Chapter 27 of Tehillim (לדוד ה' אורי – which we recite twice daily throughout Elul), David seems to think differently of himself.

אל תתנני בנפש צרי, כי קמו בי עדי שקר ויפח חמס. לולי האמנתי לראות בטוב ה' בארץ החיים...

Deliver me not over to the will of my adversaries; for false witnesses have risen up against me, and breathe out violence.  If I had not believed to look upon the goodness of the LORD in the land of the living! (Chapter 27:12-13)

On this verse the Gemara quotes David as saying to God,

רבונו של עולם, מבטח אני בך שאתה משלם שכר טוב לצדיקים לעתיד לבא, אבל איני יודע אם יש לי חלק ביניהם אם לאו!

Master of the World – I am sure that You give proper reward to the righteous in the future. Yet, I do not know if I have a portion among them or not.

What happened to the confident, self-assured Chassid? Where is the righteous David Hamelech, who declared his goodness to God? The Gemara answers: שמא יגרום החטא – "perhaps he would lose [his reward] because of sin."
David Hamelech was indeed worried. He wasn't worried about his enemies attacking him or global warming or even whether he'd be able to afford the new iPhone. Rather, he was worried about himself, and whether he'd be able to continue to serve God properly in the future.
This, says אורחות צדיקים, is the only proper type of worry.  We can and should indeed worry whether our actions over the past year have drawn us away from God. We should be concerned, even anguished over the mistakes that we've made. And we should definitely use the power of worry to keep us from sinning in the future.
It seems, then, that we're worried entirely about the wrong things.
Should we worry about Iran? That's not really in our control, and worrying about it will only make our lives more miserable. Should we even worry about our livelihoods and the exorbitant price of gasoline? Again no. We should try and work on ourselves, so that we recognize that our sustenance lies in the hands of the Creator, who "provides bread to every living creature." We of course should pray for good health and blessing, but worrying about it won't help at all.
Still, there is something we can and must worry about: ourselves. We must worry about the insidious, seductive nature of sin, so that we can learn from our mistakes and commit ourselves to improvement, return and renewal.